When aged Mr. Sobryne of Rotterdam dies, his eccentric sons, Mark, Syben, and the diminutive Little Giant, join his young and attractive mistress, Mathilde, to discuss the division of Mr. Sobryne's estate. No sooner have they collected the money than half the fortune disappears. The only suspects are the four inheritors. In an effort to win back the lost guilders, the quartet embarks upon a series of exotic adventures: Mathilde plans to buy and sell hashish in Tunisia; businessman Mark hopes to strike it rich in New York's stock market; Little Giant attempts to auction stamps in Hong Kong. They steadfastly remain together lest the thief among them escape. When all the money-making schemes end disappointingly, the brothers and Mathilde return to Rotterdam, where a surprise denouement awaits them and the reader. Though amusing, this adventure/mystery by the author of The Blond Baboon is slight; the protagonists move through the plot without significant growth or change, and the enigma of the missing money proves too flimsy to sustain the novel. In addition, the sexist treatment of the character of Mathilde is irritating and dated. (Dec.)